feat(mcp-server): tags & tax-category lookup tools (MCP Prompt 14)

[gilgardosh]

Summary

Implements Prompt 14 – Tool 2: tags and tax-category lookup (read-only) (see
docs/mcp/spec.md §8.2). Two reference-data
lookup tools.

Stacked PR: targets claude/mcp-prompt-13-charges-tool (Prompt 13, #4014).
Review/merge Prompts 09→13 first; this diff shows only the Prompt 14 changes.

Changes

• src/tools/lookups.ts
  • accounter_list_tags (allTags) → { id, name, namePath }.
  • accounter_list_tax_categories (taxCategories) → { id, name, irsCode, isActive }, with an activeOnly filter.
  • Minimal input (nameContains, limit); output is deterministically sorted (name case-insensitive, then id) and size-capped at 500 with a truncated flag. Response fields are limited to the lookup use case.
• src/tools/registry-instance.ts — both tools registered.
• Tests — sorted lookups, name filter, active-only filter, cap/truncation, business-scope enforcement, and unknown-field rejection. 160 tests total.

Validation

• yarn workspace @accounter/mcp-server test → 160 passed
• yarn workspace @accounter/mcp-server lint / typecheck / build → pass

Notes / open decisions

• Scope gate on reference data. allTags / taxCategories are org-wide (not business-filtered upstream), but I set requiresBusinessScope: true so a caller with no business membership is denied — that's the "scope enforcement" the prompt asks tests to cover, and it's a sensible gate (you browse tags because you belong to a business). The scope itself isn't used to filter the query. Easy to relax to false if reference lookups should be open to any authenticated user.
• Client-side filter/sort/cap. allTags/taxCategories take no arguments upstream, so nameContains/limit/sort are applied in the tool. Fine at reference-data sizes; if these grow large, a server-side filtered query would be better.

🤖 Generated with Claude Code

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Generated by Claude Code

[gemini-code-assist]

Code Review

This pull request introduces two new read-only lookup tools, accounter_list_tags and accounter_list_tax_categories, along with their corresponding unit tests. The feedback focuses on improving type safety in the test suite, utilizing localeCompare for more robust sorting, simplifying redundant object mapping, and polishing user-facing pluralization strings.

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[gemini-code-assist]

The byNameThenId comparison logic can be simplified and made more robust, especially for international characters, by using String.prototype.localeCompare.

function byNameThenId(a: { name: string; id: string }, b: { name: string; id: string }): number {
  return (
    a.name.localeCompare(b.name, undefined, { sensitivity: 'base' }) || a.id.localeCompare(b.id)
  );
}